The invention relates to air conditioning systems in general and particularly to an air conditioner including means for sensing the presence of hydrocarbon gases and humidity in the air being circulated within the enclosure being air conditioned. The sensing means generates electrical signals having values indicative of the concentration of gases and humidity sensed. The invention includes vent means operable by the sensing means for exhausting enclosure air when the level of hydrocarbon gases exceeds a predetermined level and for activating an audible signal when the level of hydrocarbon gases exceeds a predetermined level. The sensing means further modulates the vent means to introduce exterior air into the circulating interior air in response to level of humidity sensed relative to a pre-selected level of humidity.
Conventional air conditioners include a filter which absorbs dust particles, some gases and other impurities in the air being recirculated. In situations where the development of high concentration of impurities occurs, for instance in the event of a fire, the provision of the filter is of limited benefit if at all since the air-purifying capability of the filter is far below what may be required to counteract the prevailing concentration of impurities. This danger is particularly present, of course, when the impurities are odorless and invisible, for instance carbon monoxide. Even when the impurities are detectable by the occupants of a room, such detectability is largely without meaning if the occupants are asleep.